While pressure regulators are old and regulators providing a modulation of the pressure over a given temperature range are old, there is a continuous need for an improved pressure regulator for providing a maximum pressure at some predetermined temperature and a minimum pressure at another predetermined temperature with a broad range of temperature in which the pressure is modulated between the maximum and minimum pressures. The present invention is concerned with a pressure regulator having a diaphragm controlled valve which is loaded by an adjustable resilient member and a C-shaped spring member for providing a maximum pressure. As the loading of the adjustable resilient member is removed by a temperature responsive lever means, the C-shaped spring means provides a broad range of temperature in which the pressure is modulated. Gas valves of this kind, for instance, are used for controlling the burner in heating systems and water heaters. Since one intends to reduce the gas volume to a boiler or a water heater, an as exact as possible control by the gas control valve is required for avoiding overheating of the water because of safety reasons and also because of saving energy. This objective is difficult to achieve with valves which switch the burner on and off depending on the demand. For this purpose, a modulating gas valve is required which starts reducing the gas supply during the heating process before the setpoint temperature of the water is reached. By reducing the energy supply when approaching the setpoint temperature, a short term overheating is avoided. On the other side, care must be taken that when switching on the system, the burner immediately is operated with the maximum permitted gas pressure in order to heat up the water as quickly as possible. The invention provides a pressure regulator in which the intermediate range between maximum pressure and minimum pressure extends over a broader temperature range, that is, a broader proportional band. The invention as shown in the drawing of which